The two dimensional gel electrophoresis system which we developed will be used to study transport mutants with elevated or missing transport components. Also mutants with defective membrane structure will be analyzed this way. This analysis will be coordinated with genetic investigations attempt at raising the level of transport components. A study on the structure of the wild type and mutant Histidine-binding protein J is under way and will be pursued further: Cyanogen bromide and tryptic peptide formation; amino and carboxy-terminal analysis; full amino acid analysis. This will give us insight into the correlation between structure and function of this transport protein. The characteristics of Histidine transport in spheroplast, or other "leaky" forms of bacterial cells will be studied in order to achieve reconstitution of transport in appropriate mutants and by addition of appropriate purified components.